Hello Everyone!....It's Mr. Salah back in .......

As we all know that the test is on Friday Feb26(tomorrow!)
Today in class, we went over the review questions chp 5,using concepts c & D, and also study guide sec 7.1. Answers to these worksheet is already been uploaded thank's to Mrs. K ...any questions concerned about the answers see miss K before the test

so, all you can do today is to study and do as much questions concern to this topic as you can....
good luck with 2morrow Test ever 1!

Next Scribe Blog will be hmm!....................daveyoo!

Dynamics Review Worksheets

Dynamics Review 12 Physics

View more documents from ekozoriz.

February 24, 2010

Hi classmates,

Today, Miss K just gave us time to study and answer the review worksheet (Newton's second law). Be sure to complete it for tomorrow because we're gonna go over it. :)

Don't forget.. We have test on Friday (Dynamics Unit)




The next lucky scribe is Yassin. :)

coefficient of friction

lab in coefficient of friction
objective: to determine the value of the coefficient of friction
materials: spring scale, wooden board, level board, and protractor.

to find the F parallel: Fparallel sin teta

to find the F perpendicular: Fperpendicular cos teta

Fg=mg

to find the coefficient of friction: coefficeint of friction = F parallel / F perpendicular

to find the tan teta: F parallel / F perpendicular

suzii to scribe next

Monday, Febuary 22, 2010

Hello my fellow hard-working classmates. I hope you are all in adventurous mood!

Today in class we corrected "Grade 12 physics: Dynamics" worksheet on static equilibrium problems. I'll show the first and second questions as examples to how they are done.

1. you must solve for Ft first.
sin45= Fn/30N
Fn= 21.2132

Fn=fg
Fg= 2 x (21.2132)
=42N

2. First hint; if you are given the mass, calulate Fg right away by using the equation;
Fg=mg
=(50kg)(9.8N/kg)
=490N
Second calculate the Fn:
sin30= Fn/2Ft
Fn= (sin30)(2Ft)
We know that Fn=Fg (normal force= gravitational force)

490=(sin30)(2Ft)
2Ft=490N/sin30
=980
Here are the answers to the questions 3-5:( please check the blog for more visualization)

3. 346.5N
4. 281 N
5. 56.6N

Remeber to calculate Fg first if you are given mass, them find Fn (regarding the angle) then just substitute.

Also, today we learned about incline planes and how to draw vectors on them. Here is the terminogy:
Fg: gravitaional force is always a straight vertical line from the centre of the object on the incline plane.(arrow point towards the ground or down)

Fperpendicular is the force that is perpendicular to the object on the incline plane(arrow of vector also pointing down relative to the object.)

Fparallel is the one with 2 little lines; refers to a vector that is drawn from the tip(arrow) of Fperpendicular to Fg.

In addition I would like to give you a reminder that tomorrow we will be doing an incline lab, so it is best that you know what the three vectors stand for as mentioned above.

I thought the class today was fun!!! However I would like to thank my friend Ngan who helped me a lot. Maybe it just wasn't the best day for me at school today. It was surprising that My also very good freind Rebecca chose me. She made me feel special. HAHA

Anyways the next scribe will be.... wait let me check the scribe list......how about someone I don't know, for a change let's go with doms...

Monday, Febuary 22, 2010

Equilibrium Worksheet-Dynamics

Equilibrium 1 5

View more documents from ekozoriz.

Scribe for the 19th

Hey everyone, I hope you're having a good weekend.

So on Friday we started off by going over the 4 questions at the end of the dynamics unit booklet. So here is an explanation of the answers (they can also be found on the previous slide if my explanation doesn't make sense.)

1.a) No it can't be at equilibrium because the object will accelerate according to Newtons second law (A body will accelerate with acceleration proportional to the force and inversely proportional to the mass)

b) An example of something that is mutually perpendicular is an arrow pointing up and an arrow pointing to the left. This could not be at equilibrium as the sum of the two arrows would not equal zero.

c) An object acted upon by two not mutually perpendicular forces may be at equilibrium IF the forces look like this <---.---> This is an example of equilibrium because the sum of the forces would equal zero. However not mutually perpendicular forces aren't always at equilibrium. If the sum of the forces is not equal to zero (an arrow pointing northeast and an arrow pointing south) then they object acted upon is not at equilibrium.

2. To answer this question we must use the formula 2Ft- Fg= 0
Which we rearrange to become 2Ft= Fg
Fg is equal to mass times gravity so we can rewrite it like this, 2Ft= mg
Now plug in your values. 2Ft= (12.0kg)(9.8N/Kg)
Ft= 58.8N

3. The free body diagram for this question is (Ft) <------. ------> (Fa)
We use the formula -Ft + Fa= 0
Which can be rearranged to become -Ft= - Fa
We know that Fa = 35 N which means that Ft also equals 35 N
We are trying to solve for mass so we will write Ft= mg
m= 35N/(9.8 N/Kg)
m= 3.6 Kg

4. For this question we were trying to find the y component of the vector. (that would be the green arrow in the diagram on the previous slide) These green arrows represent the force of the tension in the wire, this force must be equal to the Fg otherwise she would not be at equilibrium. We used sine to solve for the y value because we knew one angle, remember Sin= opposite / hypotenuse.


We then corrected the Net Force worksheet. Here are the answers.
We then got a worksheet with 5 questions about dynamics. It would probably be wise to do this worksheet since I believe we are correcting it tomorrow. (:

Next scribe will beee Wahida.

Equilibrium Problems-Answers

Equilibriumworksheets

View more documents from ekozoriz.

THURSDAY, FEBRUARY 18TH, 2010

Hey Guys,

Well today we went over the answers to yesterday's test on acceleration and started a new unit. If you missed some of the solutions to the test questions, they have been posted on the previous slide.

So we read through the "Dynamics Unit" booklet, handed out yesterday, and learned about the different forces that act on objects. There are 4 questions on the last page of the handout which should be completed by tomorrow. *I would personally suggest that you do all homework that is assigned this semester if you want to recieve a high grade. The course isn't very hard in my opinion, but neglecting homework will really affect your mark. Remember practice makes perfect! :)

We also quickly went over the handout on Little Nellie Newton. I believe the answers have been loaded to the blog. If not ask a friend or the person who sits beside you in class to tell you the answers.

At the end of the period, we were given two new assignments regarding dynamics. They should also be completed by tomorrow.

I'm pretty sure that there will be a test not next week, but the week after on this unit, so make sure you pay attention and do your work, because the test we did yesterday is probably the easiest test we're going to write.

The next scribe will be Rebecca! :)

Acceleration Test Answers

Acctest

View more presentations from ekozoriz.

TUESDAY, FEBRUARY 16

Today's subsitute teacher was Ms. Bhullar (I think?). She went over the two worksheets given to us last week. Relative Motion & Relative Velocity

Relative Motion

1.a) 10.5m/s

b)6.5m/s

2.)36.9 degrees

3) 20.6m/s, 14 degrees S of E

b) 5.0s

c) 25m

4) 165m, 40 degrees S of W

5) 240m/s, 28 degrees N of E

6) 34m/s, 33 degrees N of E

7) 147 km/h, 61.3 N of W

Relative Velocity

1)6.0m/s

2) 0.73m/s

3) 2 m/s

4)168 km/h, 26.6degrees E of N

5) maximum: 5m/s

minimum: 1.0m/s

6) 16.9 m/s, 57 degrees N of W

7) 320 km/h

For the rest of the period, we worked on a new sheet given out, called "Vector Components."

There will be a test tomorrow, so don't forget to study!

Next scribe will be Maraiah.

First Scribe Post! (Class - Thursday, February 11, 2010)

Hi Classmates :)

Today, we continued our studies on Relative Velocity. In a nutshell... we discussed how frame of reference is a key thing to remember when it comes to relative velocity - all motion is relative to an observer. For example, a person walking forward at 2 m/s on a ship would appear to be walking faster to an observer on shore because the velocity of the ship would be added to the person's ground velocity. So if the ship was moving at 10 m/s, the person's velocity relative to the observer on shore would be 2 m/s + 10 m/s = 12 m/s.
So, when solving problems that involve relative velocity, the vectors of the velocities are added.

With that in mind, we also went over yesterday's homework questions from the two sheets, one entitled
4. Study Guide (on relative velocities):

The answers are as follows:
21. A
22. C
23. D
24. A, B, C, and D
25. B
26. D

and Physics 40S Relative Motion:

Case One: a) 135 km/h [E]

Case Two: a) 250 km/h [W], b) 250 km/h [E]

Case Three: a) 10 km/h [W], b) -10 km/h or 10 km/h [E], c) 70 km/h [W]

That wrapped up our one-dimensional relative motion for the lot as we moved on to two-dimensional relative motion with the worksheet... Grade 12 Physics: Relative Velocities Questions. We completed this in class, Ms. K having given us the answers, PLUS she posted them on our blog for us (check previous post). Yay thanks Ms. K. The worksheet had some 1D relative motion questions as well, but the more challenging ones (to me, lol) were the 2D relative motion questions. Since the answers and solutions have been posted, check them out for reference as you will also need to complete our two brand new worksheets (Relative Motion Problems and Relative Velocity) for homework!

So that pretty much sums up today's class.

Remember! Our test on Relative Motions has been moved from Tuesday, February 16 to Wednesday, February 17. And... finish those two homework sheets!

The scribe for next class will be Praisia.

Relative Velocity Problems: Thursday, Feb.11

Relative Velocity Problems

View more presentations from ekozoriz.

Acceleration Worksheet Answers

Acceleration Answers

View more presentations from ekozoriz.

Derivation of Acceleration Formulae

Acceleration Derivations

View more presentations from ekozoriz.

Scribe List

This is The Scribe List. Every possible scribe in our class is listed here. This list will be updated every day. If you see someone's name crossed off on this list then you CANNOT choose them as the scribe for the next class.

lpobre HYChunnie zhaio3 suzii hao jayp Maraiah sSSoColaSs

Rodel Camille

PChampion saaayana yassiN vamp doms jape

This post can be quickly accessed from the [Links] list over there on the right hand sidebar. Check here before you choose a scribe for tomorrow's class when it is your turn to do so.